Madison — Gov. Scott Walker raised an unprecedented $13.2 million over three months to fight off the recall bid against him, outdistancing his Democratic challengers and driving home the challenge they will have in beating the Republican incumbent.

Crisscrossing the country on fundraising trips, Walker has raised more than $25 million since January 2011 and has $4.9 million in cash on hand — numbers unlike any that have been seen for a political candidate in Wisconsin. Two-thirds of Walker's money came from out of state.

His stores of cash dwarf what his Democratic rivals have raised. But a report filed Monday showed an independent group supporting Democrat Kathleen Falk received $4.5 million, nearly all of it from unions and about a third of it from out of state.

Walker's fundraising is on par with that of second-tier presidential candidates. For instance, Rick Santorum raised $18.5 million between Jan. 1 and March 31, and Newt Gingrich raised a little less than $10 million during that period.

The Journal-Sentinel story is an exceptionally good piece of campaign finance reporting, filled with great details and context. It explains that the national appeal of the recall battle, as well as a wrinkle in state law that allows unlimited fundraising during recalls, has powered the governor's efforts. His donors include some familiar big money donors: Bob Perry of Swift Boat Veterans ad fame; Sheldon Adelson, a principal backer of a Newt Gingrich super PAC; Richard DeVos, co-founder of the parent company of direct marketing firm Amway.

There's a great quote in the story that captures the shock-and-awe feeling about the level of money pouring into this race from all sides, in a state that is better known for its political reformers than fundraisers.

"Wisconsin's never seen anything like this kind of money," said Jay Heck, executive director of Common Cause in Wisconsin. "This is all to persuade a relatively tiny universe of undecided voters. It'll be the highest cost per voter spent in the history of the nation in terms of the cost of persuading people."